Donald Trump takes oath of office to become 45th US president

An estimated 900,000 people were in Washington today to see Donald Trump sworn in as the United States' 45th president.

President Trump started the day with his family at St. John's Episcopal Church.

After the service, which is a tradition on Inauguration Day, he and his wife headed to the White House to be greeted by former President Barack Obama.

And then they were off to the Capitol, where Vice President Mike Pence took the oath before President Trump was sworn in.

Officials say President Trump took the oath on two bibles -- one that was given to him by his mother when he was a child, and the other the historic "Lincoln bible" used in 1861.

President Trump then gave his first speech as commander in chief. Flanked by his family on one side and the former first family on the other, President Trump pledged his allegiance to all Americans.

He spoke for about 20 minutes saying the next four years will bring change, and that the power will be "given back to the people."

"Together we will make America strong again, we will make America wealthy again, we will make America proud again, we will make America safe again," said Trump. "And, yes, together we will make America great again."